Distributed modelling of hydrodynamics and flows at the various outlets of a Mediterranean karstic aquifer

Water resources management is a major societal issue highlighted by the current climate change. Karst aquifers represent significant freshwater reserves in different regions of the world, but their exploitation is complicated by their complex behaviour. Characterizing and modeling this type of aquifer requires studying three interacting levels of heterogeneity, the matrix medium (the rock), the fracture network and the open spaces of the karst system. The standard single or double-medium approaches based on homogenization and on a Darcy-type flow model do not allow to consider the triple media aspect and assume a Darcy-type flow in the karst conduits. However, the dimensions of these conduits can induce inertial flows that must be taken into account.

The PhD student's work will involve improving a distributed modelling approach that integrates the interactions between the three media. The karst will be generated by a geostatistical tool and the flow will be modelled through embedded meshes which allow a fine 3D discretisation of the network of conduits and fractures. Statistical generation and embedded modelling form the core and originality of the subject. The resolution of the flow (via the Darcy Weisbach or Manning Strickler equations) may benefit of the research work carried out within the KARST ERC but will not constitute a fundamental research point for the student.

The distributed modelling approach will be applied to simulate the hydrodynamics and the flows at the various outlets of the aquifer associated with the Lez spring, which supplies the city of Montpellier. To quantify the heterogeneities within this strategic aquifer, the student will be able to benefit from the environment of the K3 project (PEPR OneWater) and missions to the University of Montpellier will be planned  to apply modelling tools to this field area.

Keywords: aquifers, karst, characterisation, Flow modelling, triple-media,

• Academic supervisor    Pr, JOURDE Hervé, HydroSciences Montpellier, ORCID - 0000-0001-7124-4879
• Doctoral School    ED584 GAIA, https://gaia.umontpellier.fr/, Montpellier University
• IFPEN supervisor    Dr, FOURNO André, Sciences de la Terre et Technologies de l’Environnement, ORCID - 0000-0002-9206-8111
• PhD location    IFPEN, Rueil Malmaison, France ; HydroSciences Montpellier, France
• Duration and start date    3 years, starting in the fourth quarter 2025 (Novembre 3)
• Employer    IFPEN
• Academic requirements    University Master degree in Applied mathematics, fluid mechanic, hydrogeology 
• Language requirements    French A2, English level B2 (CEFR)    

To apply, please send your cover letter and CV to the IFPEN supervisor indicated here below.